


Plutonium

by 7PercentSolution



Series: Periodic Tales [11]
Category: Sherlock (TV)
Genre: Autistic Sherlock, Chemistry, Gen, Kidlock, The Other One
Language: English
Status: Completed
Published: 2016-08-24
Updated: 2016-08-24
Packaged: 2018-08-10 20:41:07
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,627
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7860337
Author URL: https://archiveofourown.org/users/7PercentSolution/pseuds/7PercentSolution
Summary: <blockquote class="userstuff">
              <p>A silvery-white dense actinide metal that tarnishes to dull grey on exposure to air. Of all the common nuclear fuels, Pu-239 has the smallest critical mass and spontaneous fission (10 fission/s-kg), making it feasible to assemble a mass that is highly supercritical before a detonation chain reaction begins. As a result, it is the element of choice for modern nuclear weapons. The explosive potential makes it very dangerous for both of the Holmes brothers.</p>
            </blockquote>





	Plutonium

**Plutonium** **PU** **94** **244**

 

* * *

"I don't get it. It's not fair. How come _he_ knows how to do this without being taught?" The blond seventeen year old was sitting next to a thirteen year old shell at the lab bench. The difference in physique could not be more striking. The blond young man was a rugby forward, the dark haired boy was tall for his age, but thin and weedy for it. If the muttered comment was uttered with some petulance, Joshua Roles, the Harrow Physics Master, had some sympathy with Jenson's frustration. Most of the class was struggling with the mathematics behind nuclear fission. Not so Holmes, who just rolled his eyes at his lab partner's confession.

Roles had just set the class their task for the afternoon- the experiment to measure the half-life and radiation of protactinium 234, and then hypothesise the results if the substance used had been Plutonium 239. The initial experiment and then the underlying mathematics to support the hypothesis needed to be completed before the next lesson tomorrow.

"Gentlemen, I know physics is not everyone's favourite subject..." Roles sometimes struggled to get the pupils to apply themselves to the task when the temptations of sports, the arts and other extracurricular activities at Harrow sometimes proved, well… _too_ tempting, "…but knowing how to distinguish experimentally between alpha, beta and gamma radiations with reference to their ranges in air and their penetrations through different absorbers is a key element of the A level examination that you will need to master, if you expect to do well."

"So, I want you to not only conduct the protactinium experiment, but also the activity measurements for the four rays, the decay constant and half-life calculated, the nuclear reactions explained and the equations balanced. Once I see your workings, then you can retreat to your studies to work on the theoretical exercise."

The reaction of all but one of the students had been a collective groan.

"Stop griping, Jenson. Just shut up and watch." Holmes reached for the Geiger-Muller Tube and positioned it into a clip on a stand above a bottle that was sitting in a tray, so that the bottom of the tube was close to the neck of the bottle.

"What's this?" Jenson reached for the bottle, but Sherlock slapped his hand away.

"Don't touch. It has to settle, without being moved for ten minutes, or the background radiation count won't be accurate."

Jenson glowered at the kid, who didn't see the look because he'd already turned his attention to putting up the three scaffolds of different materials. The first was paper, the second a gold coloured foil, the third a layer of lead metal. "First, we have to get an accurate reading of background radiation- otherwise, the results for the real radiation will be wrong. Even _you_ should know that. The paper will block alphas, the foil will do the same for betas. The lead metal for gammas. Once we do the background counts, and get the half-life sorted, then we can get onto the fun bit or seeing how far the particles travel."

Jenson sighed. Holmes was a nutter. Fun? Fun was playing football with his mates. There was no way on earth he'd call this class "fun". While there were a few advantages to being paired with the smartest kid in the class, he hated having to endure the kid's lecturing. Holmes was in his first year at Harrow; Jenson was in what he anticipated would be his last year, because he hoped to pass his A levels and university entrance exams in the spring. It was _humiliating_ to be talked to as if he was an idiot by a kid. For the past six weeks he'd been slowly building up a deep and abiding hatred of the skinny geek. Even as his own classwork improved, his willingness to put up with the daily ritual of being shown up at every lesson declined in equal proportion. _Now that's a balanced equation._

Jenson was now determined to get his revenge. He'd spent hours trying to figure out what he could do to make the kid suffer. And he'd finally figured it out. He'd found a fellow sixth former at Bradby's who was willing to dish the dirt on the new boy. According to him, there was only one thing the kid liked more than science and that was his violin. He'd made arrangements with the guy to nick it while Holmes was in class today. Tonight he'd demand his ransom- the answers of every one of the classroom assessments from now until the end of term. And to make sure he honoured the deal, Jenson would threaten to break the violin unless Holmes complied. He was enjoying rehearsing the conversation in his head: _You can't take it with you to class or into the shower, Holmes; sooner or later, I'll get my chance to smash it, if you don't agree._

"Pay attention. Daydreaming won't finish this. If we do this right, it will take no more than twenty minutes."

Jenson groaned. Holmes was worse than any teacher when it came to telling him off. _Here it comes; he's winding himself up for the big vomit of facts._

As if on cue, Holmes was off: "Alpha radiation produces a great deal of ionisations- that's gaining or losing electrons, Jenson. That means it produces many ions per millimetre along its path, as the alpha particles push their way through material. That means alpha radiation soon runs out of energy and has a very short range. Just remember that alpha particles are helium nuclei and alpha decay removes two protons and two neutrons from the parent nucleus."

The kid started the stop watch and started taking note of the readings on the GM device, marking them on his pad. He took another breath and was off again. "Beta radiation produces fewer ionisations, so its particles can travel further than alpha particles before running out of energy. Gamma radiation produces very few ionisations along its path, so it has a very large range."

Jenson interjected, "do I really need to know all that? Or are you just spouting facts to be irritating?"

"Look, it's not rocket science." Something he'd said made the kid look sideways for a moment, and then giggle. "Well, actually, it is, but don't let _that_ scare your tiny mind."

"Just get on with it, Holmes, before I die of boredom."

"How could anyone find this _boring_ , Jenson? This is how nuclear weapons work."

Jenson just closed his eyes and let the Geek get on with jotting his numbers down.

"Wake up- or I'll tell on you for falling asleep." This was hissed at him.

Jenson grimaced and said, "Are we there yet? Wake me up when we get home."

"You are a certifiable _moron_ , Jenson. You know that making me do the practical experiment here isn't going to help you tonight. That's when you're on your own. Is that what you're going to write on your assignment: 'wake me up when we get home?'" Holmes said it in the exaggerated whine of a six year old.

That's when Jenson made his decision. _Yep- this is the last time I play this game. You're going to give me the data because I am done with this lark._ He didn't say what he meant, just gave a shake of his head. "Sorry, must have drifted off in the presence of such a black hole of boringness."

"Fine, if that's the way you want it." Sherlock didn't bother to explain what he was doing as he picked up the protactinium reactor bottle and shook it, blending the two layers – the uranium nitrate suspended in the water with the organic layer. As the two layers began to separate again, and the protactinium became active, he slipped it under the GM tube and started the stop watch. At ten second intervals, he took the count from the instrument and wrote it into his grid.

After a minute or so, Jenson was yawning. "Is that it? You just write down a number every ten seconds. How _exciting_." The sarcasm dripped from the word.

Holmes didn't even bother to look up at the older boy. "If you lack the brain power to be able to understand what the number means in terms of nuclear decay, then no amount of my explanation is going to help. Just. Piss. Off."

Unhampered by having to explain what was going on, Sherlock completed the experiment in another fifteen minutes. At the end, he didn't stop Jenson from copying the numbers off his pad. "For all the good it will do you. If you don't understand the underlying process, you won't be able to write equations, and the second bit- hypothesizing the same data for enriched plutonium 239- well, that's just way out of your reach."

"I have better things to do with my time. Holmes. I'll leave you to pack up." Jenson picked up his books and raised his hand to attract the master's attention. "We're done here, sir. Can I go to my study to complete the rest of it now?"

Roles came over to the lab table. "That was…quick. Can I see the data, please?" Holmes showed him the tables. The master nodded, "This is fine; yes, you can get on now with the second part."

"Sir, can I ask which form of Plutonium 239? Super, weapons, fuel or reactor grade?"

That made the Master smile. "Why not surprise me, Holmes? Let's make it a real challenge for you; tell me how the grade affects the results*."

Jenson grimaced. _Bloody swot. I'm looking forward to wiping that superior smile off_ _his face._ The blond sixth former didn't look back as he went out the door, seething. 

Sherlock's eyes following him out of the room. Instinctively, he knew that something in the boy's manner was different. The balance of power between him and his lab partner was changing, and it made him anxious. Something was building up, something that felt explosive. 

oOo

Mycroft poured himself another finger of brandy from the cut glass decanter on the sideboard. He went back to the dining table, which was covered in a series of neat piles of files. It was the Easter break and, while the protection of the realm meant that MI6 never slept or took a holiday, for staff such as he the absence of meetings on Maundy Thursday, Good Friday and Easter Sunday meant that work could continue off site.

Which suited Mycroft fine. The London townhouse at South Eaton Place was of course more convenient, but it was important to show his face occasionally at Parham. It was expected of him now that he was done with his time on overseas field work. Oh, there would be the necessary duties- seeing people on the estate, and, more important, being seen at the Easter Sunday service in the estate chapel. But he could manage that on autopilot. When he was at Eton, he'd done some of his best thinking while listening to the reassuringly familiar service and readings of daily chapel.

He knew there was no chance that Sherlock could be enticed to join him at Parham for the weekend. The squalor of Montague Street was his preferred habitat these days. Perhaps on Monday, he would stop by there on his way back to explain to his brother the need to keep his nose out of things that he should not be 'investigating'. He would have to have words with that DI. The knock-on consequences of Sherlock's latest unauthorised intervention last summer had led to more than nine months of rancour and public spats between the UK and Russia. A number of the piles of files on the dining table bore some relationship to that unfortunate occasion, when Sherlock slipped his leash and got involved in things that he shouldn't have.

Four uninterrupted days of thinking time. That meant banishing thoughts of Sherlock, too. He had needed the time to address a problem that had been bothering him for months. There was…something…going on. He could not put a finger on it, but it had been nagging away at his subconscious. It was a pattern too deeply hidden, even for him to identify. He would need to work at it.

Over the first two days, as he read the files, the piles changed. It was slow, methodical work. Some files were moved from one pile to another, and then the order of the files within the piles changed. Some were moved to the back of the table, others to the left or right. He spent long hours just thinking about what he was reading. Mrs Walters had her instructions- food, coffee and tea were delivered at the right times, in utter silence. He worked straight through the day and night of Good Friday, and all day on Saturday. Then at dusk he took a walk in the park to clear his head.

A brief supper was followed by a short nap sitting in the chair by the fire that had been laid in and lit for him. Then he was back at it for the rest of the night. At times, he folded his hands and rested his chin on them, staring into the middle distance without seeing anything other than what was in his mind.

One of the piles he had started with on Maundy Thursday had files with a small navy blue ribbon attached at the bottom of the right corner. There were twelve of those. By midnight on Easter Saturday, five of these had been re-distributed, allocated to some of the other piles, each one of which involved a major operation in the Russian arena where something had gone disastrously wrong. Agents had died, covers blown, operations failed to extract information, or the occasional person, from difficult circumstances. It was the truth about intelligence work. Not at all 'James Bond' -stalemates were the norm, success was rare, and there were very, very few stories that ended 'happy ever after.' Usually, it was a relentless slog against the balance of power, where a side constrained by laws, budgets and a common sense of what was acceptable confronted an opposition not interested in playing by any civilised rules. But there was something that niggled about these particular failures. There was nothing obvious. It was more a matter of timing. All had been going as well as could be expected, heading into stalemates, when abrupt failures appeared in the latter stages. Usually, if something was going to go wrong, it happened earlier.

It was the business Mycroft was in- a never-ending slog of work. Successes could not be trumpeted, without letting the other side know how to do things differently next time. Failures were …more revealing. A man's career was judged not in successes, but rather in how many disasters had _not_ been averted. That's why he had to be very, very careful with what he was doing now. After a night and three days of working, he knew now that it was likely that one person's hand was behind these failures.

On the dining table, there was a pad of navy headed paper, upon which he wrote some notes occasionally. More often than not, the page was filled with questions. Too many questions, each one of them now weighing heavy on eyelids that were beginning to droop.

He looked at one last file: the only one marked with a green ribbon. The pile it belonged to was the thwarted assassination attempt of Berezovsky. _Clumsy; I should have stopped him before he got involved._ This pile had no navy ribboned file in it. He noted that he took some comfort from that fact. He would have to work very, very hard to keep Sherlock well out of the line of fire in future.

As he retired to his bedroom to prepare for what he hoped would be five or six hours of sleep, he tried to push away his sense of frustration. He knew what he was looking for now. There was a hand at work, behind the scenes. Someone very skilled at moving events with just a tiny sideways nudge, never, ever delivered in person. And not in any way that could be connected to the real perpetrator.

The next morning he was in the front pew of the church at Parham, listening to the vicar's voice reciting the first Easter reading, from Corinthians.

 _"_ _Christ is risen from the dead:_  
and become the first-fruits of them that slept.  
For since by man came death:  
by man came also the resurrection of the dead.  
For as in Adam all die:  
even so in Christ shall all be made alive."

His mind on autopilot, he repeated with the rest of the congregation the traditional answer:

 _"_ _Glory be to the Father, and to the Son:_  
and to the Holy Ghost;  
As it was in the beginning, is now, and ever shall be:  
world without end. Amen."

As he spoke the time-honoured words, with a mind refreshed by sleep and fed by a good cooked breakfast, Mycroft was having an epiphany in private. He drew out the perpetrator's strategy, visualising it as a sort of equation. As Sherlock was wont to say, equations need to balance. When he thought of who could possibly be on the other side of all those operations, a name came to him, unbidden: FS Ford**.

It was all so superbly hidden that even when Mycroft hypothesised the existence of this _deus ex machina_ , he knew that he was not yet able to _prove_ anything. Without proof, there would be no way to stop what he now knew was an intelligence that outstripped even his own. Unfortunately, it was not as principled as he was. That was Mycroft's handicap, but one he bore stoically.

Unfortunately, the other man working behind the scenes had no such commitments or loyalties. _An accident of birth, in more ways than one._ No loyalties, no training in the obligations and responsibilities that came with wealth, status and privilege. Instead, just an aggrieved sense of _not having_ what he might have thought he was owed. So, he was using the system to take what he wanted.

The vicar's sermon was rather predictable. Well, the resurrection had been celebrated for millennia, so it was not surprising that Mycroft could filter him out and concentrate on his new found discovery. He found himself staring at the stained glass window behind the altar, installed by his grandfather after the war. The original 18th century glass had been shattered by a stray bomb aimed at the Parham airfield, to the east of the estate, on the edge of Cootham.

Mycroft wondered if his position had been reversed with that of his half-brother whether he would have had the arrogance to do such a thing- to play every side against each other. It would not be for money- at least, not in the traditional sense of taking commission or bribes; that would be too obvious, too dangerous a risk to run of implicating himself. _He's too smart for that._ Much more likely that he was dealing in information- and using it to blackmail various players. He was collecting influence and favours, more than a bank balance.

The vicar was now on the collect:

 _"_ _ALMIGHTY God, who through thine only-begotten Son Jesus Christ hast overcome death, and opened unto us the gate of everlasting life: We humbly beseech thee, that as by thy special grace preventing us thou dost put into our minds good desires, so by thy continual help we may bring the same to good effect; through Jesus Christ our Lord, who liveth and reigneth with thee and the Holy Ghost, ever one God, world without end."_

With the rest of the churchgoers, the "amen" came automatically to Mycroft.

Deep in his own thoughts, he knew that the trail could be followed. Given that given Ford's area of expertise and known activities, the information was likely to be about the trade in illegal weapons and in nuclear materials left behind when the Soviet Union disintegrated. The business defied international controls. It was the interface between failed states, terrorist cells, proliferation of nuclear weapons, the spread of organised crime networks with assets bigger than most sovereign states. The final slide into oblivion of Soviet control had opened the floodgates to criminals who were more organised than the governments replacing the old apparatchiks. For years, the Western governments tried to help- counting and cataloguing, helping with the disposal of the unwanted remnants of the Cold War. Inevitably, some things slipped through the net. It made people like Ford indispensable. His ability to move in those circles, collecting intelligence and finding the hidden stockpiles was uncanny. And the intelligence he brought back to the Western services made him…invincible.

If Mycroft's deductions were right, then taking him down would be the most difficult mission of his career. But get it wrong, tip off the man he was pursuing, and he knew that he would not survive. The man he was up against was more than capable of sending an executioner. In fact, it would suit his private purposes very much if there was a sudden vacancy in the viscountcy of Sherringford. Especially with Sherlock's current record of drug abuse, rehabilitation and general inability to achieve anything approaching stability. Without Mycroft to protect him, Sherlock would be hopelessly vulnerable to the plots of a half-brother he didn't even know he had. This was _very_ dangerous territory, and not just for Mycroft.

He felt an unexpected emotion creep up on him: anxiety. It followed him out of the church and into the spring sunshine.

* * *

 

**Author's Note:**

> Author's note:* for Sherlock's hypothesis, the grade of Plutonium 239 is important, as the element is formed when uranium 235 goes through fission, leading uranium 238 to absorb the two to three neutrons released, forming PU-239 and 240. PU is classified according to the percentage of the contaminant plutonium-240 that it contains: super grade is 2–3% contaminated; weapons grade less than 7%; fuel grade 7–18%; reactor grade 18% or more. The presence of Pu240 will alter the decay rate of the sample accordingly. Modern nuclear weapons, many of which are delivered in small, compact payloads on cruise missiles, use PU-239. On submarines where crew live in close proximity to the weapons, only supergrade is used, because it emits less radiation. ** if you want to know who Ford is, check out Ex Files Chapter 38 over on FanFiction.


End file.
